For connecting a syringe and a counterpart connection device such as a needle or a connection port of infusion tubing or an infusion pump, or the like, the simple luer fitting system is generally employed, which is achieved by fitting of a male luer provided at the tip of the former to a female luer provided in the latter. Further, in addition to the simple luer system, another type of system (luer lock system) has been employed for connection to, e.g., infusion tubing, where a female luer is screw-cramped around itself for the purpose of securely fix the fitting to prevent its easy displacement by external forces. As syringes that are also adapted to the luer lock system, there are known such ones that are equipped with a female-threaded plastic sleeve at their tips surrounding the male luers (see Patent Document 1, FIG. 2). This configuration has made it possible to provide, using a single type of syringes, two types of products i.e., one type adapted only to the simple luer system and the other adapted to the luer lock system.
FIG. 1 illustrates this type of luer lock syringe that is commonly used, which is equipped at its tips with the above type of female-threaded sleeve 2 (shown in a cross sectional view) and a cap 3. In the figure, numeral 4 indicates a gasket which is pressed from behind to advance within the syringe 1, numeral 5 an injectable liquid enclosed in the syringe 1. FIG. 2 illustrates an enlarged view of the tip portion of the above-mentioned luer lock syringe. As seen in FIG. 2, the sleeve 2 is attached by fitting it around a squeezed portion 6 at the root of the male luer at the tip of the syringe 1.
In the case of this conventional luer lock syringe, since the sleeve 2 is to be attached by fitting around the squeezed portion 6 at the root of the male luer of the syringe 1, attachment of the sleeve 2 is blocked if the cap 3 is already fitted on the male luer at the tip of the syringe 1. On the other hand, in order to fill the syringe 1 with an injectable liquid, the cap 3 must be fitted beforehand to seal the tip of the syringe. Consequently, the sleeve 2 must be attached to the tip of the syringe 1 before the cap 3 is fitted at the tip of the syringe, therefore, necessarily before the syringe 1 is filled with the injectable liquid.
Since injectable preparations must be supplied under a sterile condition, it is necessary that the syringe 1, which must be sterilized, must be filled with an injectable liquid in a sterile environment (in an aseptic room). The syringe 1, the cap 3 and the gasket 4, therefore, must be sterilized in advance and then brought over into an aseptic room while keeping them in a sterile condition. As aforementioned, since a conventional luer lock syringe is filled with an injectable liquid, with its sleeve 2 already attached to it, the sleeve 2 also must be sterilized in advance and, while being kept sterile, brought over in a aseptic room. In this circumstance, before filling a luer lock syringe with the injectable liquid, components are conventionally brought over into the aseptic room following either of the two procedures mentioned below.
(1) A syringe having a female-threaded sleeve attached to it, a cap (either separately or as attached to the syringe) and a gasket are brought in the aseptic room for filling with an injectable liquid.
(2) A syringe, a female-threaded sleeve, a cap and a gasket are brought in the aseptic room for filling with an injectable liquid, all as separate components.
According to the above procedure (1), a syringe must be sterilized in advance, with a female-threaded sleeve (or further a cap) attached to it, before they are brought in. Though a syringe itself may be subjected to a convenient procedure of hot air sterilization if it is made of glass, a plastic female-threaded sleeve attached to it cannot withstand it. Therefore, they are sterilized by the process of gas sterilization, autoclave sterilization, gamma ray sterilization or electron beam sterilization, and the like. Whatever the method for sterilization is employed, attachment of the sleeve (or further the cap) to the tip of the syringe before sterilization must be done in an environment that would not cause contamination with microbes, and this leads to substantial amount of costs.
According to the above procedure (2), although it is an advantage that pre-sterilization assembling of the components is not necessary, and therefore each of the components may be sterilized separately, it needs a sterility control, which is costly, for an increased number of sterilized components is to be brought over into the aseptic room, while they all are kept sterile. In addition, since a process of fitting a female-threaded sleeve around the tip of the syringe in the aseptic room is placed prior to filling with the injectable liquid, it is necessary to sterilize and assemble machines and their parts used for this purpose. This makes it difficult to improve the production efficiency as a whole. Further, fracture of the male luer at its root and damage to the sleeve are apt to happen when the sleeve is being attached. And, when such a problem or improper fitting of the both parts does happen, cleaning of the line and readjusting of the machines are extremely difficult to perform in the special circumstance in the aseptic room, thus greatly lowering the productivity.
Another injection device is further known as providing an injection device adapted to the luer lock system through combination of a syringe having a simple luer-type tip and a certain additional part, i.e., an injection device comprising a cylindrical injection device body (i.e., holder) having at its distal end a threaded cylinder portion, a cylindrical ampoule inserted in it, with the tip of the ampoule is fixed by fitting the conical portion for engagement at the root of the male luer in a conical bore made in the injection device body, and a removable securing sleeve which secures the proximal end portion of the ampoule (see Patent Document 2). However, even with this injection device, it is impossible to insert the syringe into the injection device body when a cap is attached to the tip of the syringe, for the holder (therefore the threaded cylindrical portion) and the ampoule (i.e., syringe) are secured around the root of the male luer. Therefore, the process of filling with the injectable liquid is possible only after the syringe is inserted in the holder and the cap is attached to the male luer positioned at the distal end of the holder. Thus, there are the same problems as mentioned, also with regard to above procedures (1) and (2).
As a holder to make an injectable device adapted to the luer lock system from a simple luer-tip syringe, there is known a holder which, utilizing a syringe having a finger rest projection at its proximal end, secures the projection by sandwiching it at the proximal end of the holder (see Patent Document 3). However, with conventionally used syringes having a finger rest projection, as there are of many types and sizes in the length of the syringe barrel and in the thickness of the projection, use of such a projection as an element for holding the syringe would cause unstable holding and also make the position of the tip of the syringe likely to vary in the holder.
As aforementioned, with conventional luer lock syringes, it is difficult to improve the efficiency of production processes from sterilization of their parts to filling with an injectable liquid, thus presenting factors that increase the production cost as a whole.
Besides the above-mentioned problems, there are such types, among counterpart connector devices to which a luer-type tip syringe is to be connected, that are not adapted to the luer lock system and interfere with the female-threaded sleeve, thereby preventing connection from being achieved. When connection is to be made between a syringe and such types of devices, it is a routine practice that the cap is removed from the male luer and then the female-threaded sleeve is ripped by force, using pliers or the like, from the tip of the syringe. As a result, there have arisen frequent problems such as fracture of the male luer and contamination of the tip. With this regard, the injection device or the holder described in the aforementioned Patent Document 2 or 3 have further problems that, since the threaded potion at their distal end cannot even be removed and, further, they do not allow the ampoule (i.e., syringe) to be pulled out from the body (i.e., holder) of the injection device without avoiding dropping off of the cap, they cannot be used with such a counterpart connector device that can only be connected to an exposed type male luer of the simple luer system.    [Patent Document 1] U.S. Pat. No. 6,250,052    [Patent Document 2] Japanese Patent Publication H1-56783    [Patent Document 3] Japanese Patent Application Publication H10-155905